1. Field of the Invention
The present invention generally relates to an electrical connector assembly, and more particularly to an electrical connector assembly having a placement member assembled thereon to provide a vacuum suction pick-up surface.
2. Description of Related Art
Vacuum suction mechanisms are well known in the electronic assembly art and are used for retrieving electronic components, such as connectors, from a supply source and transferring the component by applying negative air pressure to the component and placing the component on a printed circuit board in a preselected position for soldering. Generally, the vacuum suction mechanism comprises a suction nozzle. A connector is grasped by the suction nozzle and is robotically transferred to the position on the printed circuit board with great accuracy.
Most electrical connectors, however, are devoid of flat, solid surface suitable for being grasped by the suction nozzle. To overcome this problem, transfer or placement members having a flat, non-porous surface have been developed for attaching to connectors. Such connector placement members are described in the U.S. Pat. Nos. 5,688,133; 4,396,245; 5,249,977; and 5,681,174. These patents describe placement members designed for an electrical connector having two opposite sidewalls extending upward from a connector body. The placement members have a flat top surface suitable for being grasped by a vacuum suction nozzle and downwardly extending legs for engaging with the sidewalls of the connector body.
For example, FIGS. 4 and 5 show the placement cover of U.S. Pat. No. 5,688,133. The placement cover 8 is made of metallic material, is formed by stamping, and has a cover plate 80 with a flat top surface. Two pairs of resilient arms extend downwardly from each end of the cover plate 80. Each pair of arms has an outer engagement arm 81 and an inner engagement arm 82. The outer and inner arms 81, 82 are spaced apart from each other to define a receiving space 83. The dielectric housing 90 of connector 9 has a pair of opposing longitudinal sidewalls 901 and a center wall (not labeled). A pair of slots 902 are defined between the sidewalls 901 and the center wall. When the placement cover 8 is assembled on the connector 9, each space 83 receives a sidewall 901 of the connector housing 90 and the outer and inner arms 81, 82 abut against the outer and inner surfaces of the sidewalls 901. However, since the placement cover 8 of the ""133 patent is made of metal, the shape and dimension of the outer and inner engagement arms 81, 82 must be precisely formed so that they mate with the connector reliably. The manufacturing method therefore, adds expense.
U.S. Pat. No. 6,439,901, which has the same assignee as the present invention, discloses a placement member made of a resilient dielectric material, as shown in FIG. 6. The placement member 7 is assembled on a connector 6 and has a pair of downwardly projecting legs 71 at each end thereof. A retaining foot 710 is formed at an end of each leg 71 for abutting against an inner surface of longitudinal sidewalls 61 of the connector 6. The manufacturing method of the placement member 7 is simple. However, since the placement member 7 has no positioning element, the placement member 7 may end up being positioned in any place along the longitudinal direction N. The precision of the robotic assembly, thereof, is reduced.
Hence, an electrical connector with an improved placement member is desired to overcome the above-mentioned disadvantages.
Accordingly, one object of the present invention is to provide an improved placement member with guiding, or positioning legs.
Another object of the present invention is to provide an electrical connector assembly having an improved placement member reliably and precisely assembled on an electrical connector.
In order to achieve the above-mentioned objects, an electrical connector assembly in accordance with the present invention comprises an improved placement member assembled on a connector. The placement member provides vacuum suction surface for vacuum placement mechanism to attach to. The placement member is made of a resilient insulative material and comprises a main plate, which has a substantially planar upper surface and an opposite lower surface, a plurality of positioning legs extending downwardly from said lower surface, and two U-shaped retaining portions extending from the two lateral edges of the main plate. Each retaining portion has a beam portion connecting with the edge of the main plate and a pair of projecting legs extending downwardly from ends of the beam. The pairs of projecting legs abut against the inner surfaces of the connector body and the positioning legs are positioned in slots on the outer surfaces of the connector sidewalls.